How billet AR-15 receivers are made

SI Defense manufactures AR-15 lower and upper receivers that are machined out of solid aluminum billet blocks.

Picture 12-21
Two soon-to-be receivers being sprayed with coolant by the CNC machine

They have photos of the process and a video showing the CNC machine in operation. Very interesting.

Thanks to Health for the link.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • jdun1911

    They should take full advantage of the billet 6061-T6 aluminum. It allows interesting designs to be produce.

  • I’d like to have one billet lower just because of the cool factor!